1. Field of the Invention
The invention generally relates to measurement results collection for Minimization of Drive Tests (MDT), and more particularly, to apparatuses and methods for handling measurement logging configuration.
2. Description of the Related Art
In a typical mobile communication environment, a user equipment (UE), including a mobile telephone (also known as a cellular or cell phone), a laptop computer with wireless communications capability, or a personal digital assistant (PDA) etc., may communicate voice and/or data signals with one or more service network. The wireless communications between the UE and the service networks may be performed using various wireless technologies, such as the Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, LTE-Advanced technology, and others. Generally, an operator needs to run manual drive-tests to adjust network settings for performance optimizations, including radio coverage optimization, mobility optimization, network capability optimization, channel optimization, Quality of Service (QoS) verification, network planning, and others. In order to reduce the cost and time consumed for the manual drive-tests, a Minimization of Drive Tests (MDT) concept has been proposed, which requires the user equipment (UE) to log its measurement results and report the measurement logs (referred to herein as MDT logs) to the service network, so that the operator may analyze the MDT logs and adjust the network settings without too much requirement for manual drive-tests.
Take the Universal Mobile Telecommunications System (UMTS) technology in compliance with the 3GPP TS 37.320 specification (referred to herein as the 37.320 specification), 3GPP TS 25.331 specification and 3GPP TS 25.304 specification or Long Term Evolution (LTE) technology in compliance with the 3GPP TS 37.320 specification, the 3GPP TS 36.331 specification, and the 3GPP TS 36.304 specification as an example. After a UE is connected to a UMTS Terrestrial Radio Access Network (UTRAN) or evolved-UTRAN (E-UTRAN) and is configured to be in the RRC_CONNECTED mode, the UTRAN or E-UTRAN may configure the UE for performing logging of measurement results in the RRC_IDLE mode, by transmitting a LoggedMeasurementConfiguration message to the UE, as shown in FIG. 1. The LoggedMeasurementConfiguration message indicates the configuration parameters for periodic MDT logging in the RRC_IDLE mode, including a value for a periodic logging timer, i.e. loggingInterval. When receiving the LoggedMeasurementConfiguration message, the UE starts the periodic logging timer with the indicated value. However, when the UE is later configured to leave the RRC_CONNECTED mode, all running timers except the timer T320 are stopped. Consequently, the UE does not perform periodic MDT logging in the RRC_IDLE mode as it is supposed to do, since the periodic logging timer has been stopped.